The present invention relates to a cursor position control means device of the type commonly referred to as a trackball device. Such devices are used, for example, to control the movement of a cursor of a video display, as in a video game.
Trackball devices include a housing having a circular opening therein and a plurality of rotatable supports, at least two of which are respectively rotatable about orthogonally related axes. A ball is loosely seated on the supports with a portion of the ball projecting through the opening, so that the user can manually rotate the ball. The rotatable supports respectively respond to corresponding components of rotational movement of the ball. The supports are respectively connected to signal generating devices which produce signals indicative of the speed and direction of rotation of the supports. The two orthogonally related supports respectively correspond to the X and Y directions of movement of the cursor, so that the speed and direction of movement of the cursor in the X and Y directions correspond respectively to the speed and direction of rotation of the associated supports.
In prior trackball devices, each support included a horizontal shaft journaled into roller bearings in turn carried by pillow blocks. Although these work reasonably well, the use of roller bearings undesirably adds cost to the trackball device. Also, even with such roller bearings, friction still was present.